Foam-water sprinkler device

ABSTRACT

A foam water sprinkler device which has a tubular body and within the body there is a ball splitter. The body has a converging bore, a throat of reduced bore and an enlarged bore portion and the ball splitter is located either downstream or partially within the throat.

United States Patent Larah Mar. 5, i974 [54] FOAM-WATER SPRINKLER DEVICE 3,199,790 8/1965 Giesemann 239/432 X 4 75 Inventor: David Arthur Larah, Salford, 9/1972 Smdgm 239/432 X England [73] Assignee: Mather & Platt Limited, Primary ExaminerAllen N. Knowles I Manchester, England Assistant ExaminerMicha.el Y. Mar

Attorney, Agent, or FirmSughrue, Rothwell, Mion, [22] Filed. Mar. 23, 1973 Zinn & Macpeak [21] Appl. No.: 344,398

[30] Foreign Application Priority Data Mar. 7, 1973 Great Britain lll58/73 [571 ABSTRACT [52] HS. Cl. 239/432, 169/15 A m water prinkler devi e which has a tubular [51] Int. Cl... B05]: 7/06 body and within the body there is a bail splitter. The [58] Field of Search 239/432, 461, 428,5; 169/14, body has'a converging bore, a throat of reduced bore 169/15 and an enlarged bore portion and the ball splitter is located either downstream or partially within the 6 1 References Cited throat.

UNITED STATES PATENTS 3,051,397 8/1962 Hanson".. 239/432 '4 Claims, 8 Drawing Figures PATENTEU 5 74 SHEET 1 BF 4 EXPANSION PATENIEUIIIR 5l974 3.795.368

SHEET 2 III 4 RATIO DEFLECTOR POSITION FIG,5

cooo INDIFFERENT V FOAM SOLUTION QUALITY FIGb EXPANSION RATIO PATENTEU 51974 SHEET 3 [IF 4 Ow Om FOAM-WATER SPRHNKLER DEVICE This invention relates to foam-water sprinkler devices for tire extinguishing systems and more particularly has to do with sprinkler heads which form and distribute a mechanical fire-extinguishing foam when a foam compound and water together known as a foam solution are discharged therethrough from a source of foam compound and water under pressure and which distributes water when water alone is discharged therethrough from a source of water under pressure.

In certain commercial areas, for example where a liquid fuel fire hazard occurs the putting out of fires by water alone is not regarded as sufficiently certain or rapid and fire extinguishing equipment is employed which forms and distributes mechanical foam from a mixture of foam compound and water. The supply of water in such a system is normally still plentiful even after the supply of foam compound is exhausted, and although generous amounts of foam compound are provided, prolonged discharge will eventually exhaust this compound. At such time it is expected that the fire will be extinguished, but for the rare case when it has not been completely put out and for the prevention of re-ignition when the fire has been put out, continued discharge of water alone to further control the fire or prevent such re-ignition is desirable.

Accordingly, efforts have been made in this field to provide sprinkler devices which not only properly form and distribute the foam but also properly distribute water alone after the foam compound is exhausted.

Thus, for a foam-water sprinkler system, it is desirable to keep the size of the sprinkler device as small as possible, to provide a sprinkler device which can be used either in an upright or pendant position with a minimum of modification, to provide a sprinkler device which forms a foam of such quality that the blanket of foam which accumulates on the surfaces in the protected area is not washed away or greatly damaged by the subsequent discharge of water-alone, to provide a sprinkler device which widely and evenly distributes this foam, and to provide a sprinkler device which widely and evenly distributes water alone.

British Pat. Specification No. 976,867 discloses a sprinkler device which achieves each of these desirable objects to a degree. The said Patent Specification discloses a sprinkler device in the form of a nozzle presented to one open end of a short barrel which has a first passageway portion tapering to a throat,-and in which the throat is followed by an expansion second passageway portion larger than the throat and extending therebeyond, there being a splitter in the path of the nozzle and in the upstream end of the first passageway portion, and there being a deflector spaced beyond the open end of the second passageway portion.

With this structural arrangement the stream of water and foam compound issuing from the nozzle and impinging on the splitter is directed against tapering walls which constrict the fluids towards the throat. This provides an abrupt change in fluid direction and simultaneously compacts and intimately mixes the fluids as they approach the throat. Beyond the throat in the second expansion passageway portion the fluids are further mixed and their direction of movement is oriented for final discharge against the deflector.

As the same time with this structural arrangement, discharge of water alone from the nozzle provides a water distribution in the protected area comparable in pattern and volume to the foam distribution, and this is a particularly fortunate feature because of the great difference in the properties of foam and water.

It has been found that the quality of the foam produced by such devices depends to a great degree on the condition of the foam compound which deteriorates with age, and that even samples of foam solution of the same batch produced varying qualities of foam when prepared from different drums. Such unpredictable foam conditions are highly undesirable and necessitate frequent monitoring of the condition of the foam agent.

Accordingly, experiments were made to determine the effect on foam quality of moving the splitter within the barrel. It has surprisingly been found that a signifi cant improvement of foam quality and consistency is achieved if the splitter is moved further downstream.

According to the present invention, there is provided a foam-water sprinkler device comprising a nozzle for connection to a source of water and foam compound under pressure and having a discharge orifice of reduced diameter, said nozzle being connected by legs to a hollow tubular barrel axially aligned with the nozzle and open at both ends, the inlet end of the tubular barrel being spaced from the discharge end of the nozzle so that in use, air is entrained and a mixture of air and liquid passes along the barrel, the discharge end of the latter being spaced by supporting struts from a cone deflector which creates the distribution pattern of the final foam on the area to be protected from fire, the barrel comprising in sequence in the direction of air/- liquid mixture flow, a converging bore, a throat or por tion of reduced bore, and an enlarged bore portion extending to the barrel outlet adjacent to the cone deflector, there being a splitter located either downstream of, or partially within, the throat or portion of reduced bore to split up the air/liquid stream.

Preferably, the splitter is dimensioned so as to present a convex, substantially hemispherical surface to the nozzle orifice. For example, the splitter may be a ball supported centrally in the barrel and has a diameter of a similar size to the discharge orifice of the nozzle.

In order that the present invention may be more readily understood reference will now be made to the accompanying drawings, in which:

FIG. 1 is a partly sectioned side elevation view of a foam-water sprinkler device in accordance with the present invention;

FIG. 2 is a cross-sectioned side elevation view taken on line 2-2 of FIG. 1;

FIGS. 3 and 4 are cross sectional views taken on lines 33 and 44, respectively, of FIG. 2; and

FIG. 5 illustrates the expansion ratio, i.e. the ratio of the volume of foam produced to the volume of solution used to produce it, of a foam solution for different splitter positions;

FlGS. 6, 7 and 8 illustrate the effect on the expansion ratio obtained with the described embodiment of the invention and with prior art devices of foam solution quality pressure and induction respectively.

Referring now to the drawings the foam-water sprinkler device shown comprises a nozzle 10 externally threaded at 12 for connection to a source of water and foam compound under pressure, for example, a piping system (not shown) conducting such materials to the area to be protected from fire.

The nozzle passage 14 is slightly restricted at the discharge orifice 16 by a decrease in diameter, as shown. Secured to the nozzle by short legs 18 is a hollow tubular barrel 20 axially aligned with the axis 30 of the nozzle and open at both its inlet end 22 and its discharge end 24. The end 22 is spaced somewhat from the discharge orifice 16 of the nozzle, and similarly an axially located cone deflector 26 is spaced from the open discharge end 24 of the barrel by short supporting struts 28.

When fluid under pressure, for example, a mixture of foam compound and water, issues from the discharge orifice 16 of the nozzle 10 it is in the form of a solid stream which enters the open inlet end 22 of the barrel along the barrel axis 30 and strikes a ball-shaped splitter 32, supported beneath the barrel passageway 34 on the barrel axis by a pair of rods 36. This impact fans the stream out against the barrel wall downstream of the splitter. In the embodiment shown the ball splitter 32 has a diamter slightly greater than that of the orifice 16 so that substantially the entire stream impinges on the splitter even if the stream-expands somewhat between the nozzle orifice and splitter.

The ball splitter is located downstream of a first barrel passageway portion 30a which is defined by straight sided walls of the barrel having a converging taper between the upstream end of this first portion and a throat 30b. The horizontal cross section of this first passageway portion is substantially circular.

Just beyond the throat 30b in the direction of flow the barrel passageway opens out along a short portion 30c with a taper much more abrupt than the taper in portion 30a to join a final expansion portion 30d having in this embodiment substantially the same diameter as the upstream end first portion. The rods 36 which support the splitter 32 are arranged in the short portion 30c.

The stream of foam solution passes through the first portion 30a, strikes the splitter, and is fanned out against the barrel walls. The movement of the thus agitated solution along the barrel passageway entrains air from the open barrel inlet end 22 so that a mixture of air and solution progresses along the barrel. This mixture is the beginning of the foam which this sprinkler device is intended to form and the further interaction ofthe solution and air along the remainder of the barrel and against the deflector completes and distributes this foam.

To assist in the proper entrainment of air from the open inlet end 22 the barrel passageway has another portion 30e upstream of portion 30a. At the inlet end 22 this portion has a diameter substantially greater than the diameter of the upstream end of passageway portion 30a so that air can be freely drawn into the barrel even though the nozzle is located across the inlet end 22 and to some extend blocks it. This enables the nozzle 10 to be located close to the barrel to keep at a minimum the overall length of the device.

In the embodiment shown the enlarged diamter of passageway portion 302 at the inlet end 22 is achieved by a continuation upstream along portion 30e of the constant taper of portion 30a. This is a preferred arrangement because of its simplicity and smooth flow characteristics.

The splitter 32 preferably presents to the stream a splitting surface on which an axial projection of the discharge nozzle orifice 16 substantially entirely falls so A OLD that substantially the entire stream issuing from the nozzle strikes the splitter and is fanned out thereby. This surface is preferably substantially a hemisphere, as is the case, for example, when the splitter 32 is a complete ball having a diameter larger than the diameter of the nozzle opening 16.

One advantage of a hemispherical surface is that it has a large central portion of its surface area which is suitably blunt to agitate the solution striking this portion and at the same time has a large peripheral portion of its surface area which is suitably angled to redirect and fan out the solution striking there without greatly retarding the velocity of that solution.

Another advantage is that, by using a ball for a splitter, manufacture is greatly simplified because the splitting surface need not be carefully orientated with respect tothe nozzle. It is enough to locate the ball in the path of the stream from the nozzle and twisting or turning of the ball does not change the orientation of the splitting surface.

The throat 30b is preferably substantially larger in area than the axially projected area of the splitter.

Beyond the throat 30b the passageway preferably opens outwardly abruptly to the expansion portion which is preferably cylindrical and has a diameter substantially equal to the diameter of the upstream end of first tapered portion 30a.

The deflector 26 is in the form of a cone axially aligned with the barrel axis 30 and having its apex 38 presented to the open barrel end 24. On issuing from this end the frothy mixture of solution and air is further agitated by impingement on this cone and is redirected thereby outwardly against suitable lines 40 which extend beyond the cone edge and create the distribution pattern of the final foam on the area to be protected from fire. In the drawings these tines 40 are formed on a separate plate 42 secured to the base of the deflector cone 26 by a rivet 44 integral with the deflector 26, and these tines are disposed to distribute the foam to the floor of the protected area when the device is in the pendant position shown. Other tine shapes (not shown) can be used in a well known manner to distribute the foam to the floor when the device is used in another position, for example, an upright position.

Referring to FIG. 5 in which the splitter position is measured from the portion thereof closest to the upstream end of the device, the effects on the foam expansion ratio of varying the axial position of the splitter 32 are illustrated. It will be seen that a peak performance is obtained when the splitter 32 is located either downstream of or partially within the throat. This performance may be seen to be significantly better than that obtained when the splitter is in the position according to the prior art, which is shown in dotted lines.

A series of tests were carried out to compare the performance obtained with devices according to the present invention hereinafter referred to as NEW," with the performance of prior art devices, hereinafter referred to as OLD.

In a first test, foam compound was taken from a good sample and passed after dilution with water either through a NEW" or an OLD" device at a pressure of 30 psi. and induction of 6 percent. The results are set out in Table 1:

Test Device Expansion Ratio 1 Air temperature 12C Foam solution temperature: 11C

It will be seen from Table 1 that the expansion ratios obtained are better and more consistent with the NEW device. I

In a second test, an indifferent sample of foam compound from the same batch but a different drum was used under the same conditions as in the first test. The results are set out in Table 2.

Test Device Expansion Ratio A OLD 4.8:1 B OLD 4.8:1 C NEW 8.121 D NEW 7 4 1 Device OLD OLD OLD NEW NEW NEW ir Temperature: 10.5"C

xp nsion Ratio E a 4.4 l 4. l 3.9 1 5.7 1 6.01 6. 1

A D C D E F A It will be seen from Table 3 that the new device offers significant advantages even when used with old foam compound.

Further tests were carried out and from them the dependance of Expansion Ratio on Foam compound Quantity for the NEW and OLD devices was determined to be that illustrated by curves A and B respec- 6 tively in FIG. 6.

. Further tests to determine the effects of pressure and induction on expansion ratio for NEW and OLD devices were carried out, and the results are illustrated in FIGS. 7 and 8, curves A referring to the NEW device and curves B to the OLD device.

What is claimed is:

1. A foam-water sprinkler device comprising a nozzle for connectionto a source of water and foam compound under pressure and having adischarge orifice of reduced diameter, said nozzle being connected by legs to a hollow tubular barrel axially aligned with the nozzle and open at both ends, the inlet end of the tubular barrel being spaced from the discharge end of the nozzle so that in use, air is entrained and a mixture of air and liquid passes along the barrel, the discharge end of the latter being spaced by supporting struts from a cone deflector which creates the distribution pattern of the final foam on the area to be protected from fire, the barrel comprising in sequence in the direction of air/- liquid mixture flow, a converging bore, a throat or portion of reduced bore, and an enlarged bore portion extending to the barrel outlet adjacent to the cone deflector, there being a splitter located either downstream of, or partially within, the throat or portion of reduced bore to split up the air/liquid stream.

2. A foam water sprinkler device according to claim 1, wherein the portion of the splitter which is farthest upstream in the barrel is located in the thinest portion thereof.

3. A foam water sprinkler device according to claim 11, wherein the splitter is a ball supported centrally in the barrel and has a diameter ofa similar size to the discharge orifice -of the nozzle.

4. A foam water sprinkler device according to claim 1, wherein the barrel opens outwardly abruptly downstream of the throat to an enlarged bore portion which has a diameter substantially equal to the diameter of the inlet end of the converging bore. 

1. A foam-water sprinkler device comprising a nozzle for connection to a source of water and foam compound under pressure and having a discharge orifice of reduced diameter, said nozzle being connected by legs to a hollow tubular barrel axially aligned with the nozzle and open at both ends, the inlet end of the tubular barrel being spaced from the discharge end of the nozzle so that in use, air is entrained and a mixture of air and liquid passes along the barrel, the discharge end of the latter being spaced by supporting struts from a cone deflector which creates the distribution pattern of the final foam on the area to be protected from fire, the barrel comprising in sequence in the direction of air/liquid mixture flow, a converging bore, a throat or portion of reduced bore, and an enlarged bore portion extending to the barrel outlet adjacent to the cone deflector, there being a splitter located either downstream of, or partially within, the throat or portion of reduced bore to split up the air/liquid stream.
 2. A foam water sprinkler device according to claim 1, wherein the portion of the splitter which is farthest upstream in the barrel is located in the thinest portion thereof.
 3. A foam water sprinkler device according to claim 1, wherein the splitter is a ball supported centrally in the barrel and has a diameter of a similar size to the discharge orifice of the nozzle.
 4. A foam water sprinkler device according to claim 1, wherein the barrel opens outwardly abruptly downstream of the throat to an enlarged bore portion which has a diameter substantially equal to the diameter of the inlet end of the converging bore. 